Disk for HP 9825B

There are some photos in my flickr account of dismantling an HP9820 ROM module. The principle is the same. The modules are assembled by aluminium studs which ahve barbs down the stem. The basic method is to get a screwdriver into the crack at oen corner of the module, melt a little solder onto th ead of the studd in that corner (it won't stick, the aluminium oxide film prevents that [1]) and then after hodlign the iron on for a few seconds, to force that corner of the module apart. The problem is that the top section fo the mdoule, nearest the head of the stud, will softne too, and if you are unlucky, the stud will pull through there ratherh than out pf the lower part which is what you want. Incidentally, for reassmebly, I always use self-tapping screws. I do not try to refit these infernal studs. [1] As an aside, it is possible tosodler to aluminium with normal lead-tin solder and the resin core flux. I have done it when I had to attach awire to an aluminium electrode. I think it would make life a lot easier. I will try to dig out my schematic of the 98228 to check. -tony